llvm-6502/lib/Target/PowerPC/PPC.h

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//===-- PPC.h - Top-level interface for PowerPC Target ----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the entry points for global functions defined in the LLVM
// PowerPC back-end.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_POWERPC_H
#define LLVM_TARGET_POWERPC_H
#include "MCTargetDesc/PPCMCTargetDesc.h"
#include <string>
// GCC #defines PPC on Linux but we use it as our namespace name
#undef PPC
namespace llvm {
class PPCTargetMachine;
class FunctionPass;
class ImmutablePass;
class JITCodeEmitter;
class MachineInstr;
class AsmPrinter;
class MCInst;
Implement PPC counter loops as a late IR-level pass The old PPCCTRLoops pass, like the Hexagon pass version from which it was derived, could only handle some simple loops in canonical form. We cannot directly adapt the new Hexagon hardware loops pass, however, because the Hexagon pass contains a fundamental assumption that non-constant-trip-count loops will contain a guard, and this is not always true (the result being that incorrect negative counts can be generated). With this commit, we replace the pass with a late IR-level pass which makes use of SE to calculate the backedge-taken counts and safely generate the loop-count expressions (including any necessary max() parts). This IR level pass inserts custom intrinsics that are lowered into the desired decrement-and-branch instructions. The most fragile part of this new implementation is that interfering uses of the counter register must be detected on the IR level (and, on PPC, this also includes any indirect branches in addition to function calls). Also, to make all of this work, we need a variant of the mtctr instruction that is marked as having side effects. Without this, machine-code level CSE, DCE, etc. illegally transform the resulting code. Hopefully, this can be improved in the future. This new pass is smaller than the original (and much smaller than the new Hexagon hardware loops pass), and can handle many additional cases correctly. In addition, the preheader-creation code has been copied from LoopSimplify, and after we decide on where it belongs, this code will be refactored so that it can be explicitly shared (making this implementation even smaller). The new test-case files ctrloop-{le,lt,ne}.ll have been adapted from tests for the new Hexagon pass. There are a few classes of loops that this pass does not transform (noted by FIXMEs in the files), but these deficiencies can be addressed within the SE infrastructure (thus helping many other passes as well). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181927 91177308-0d34-0410-b5e6-96231b3b80d8
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FunctionPass *createPPCCTRLoops(PPCTargetMachine &TM);
#ifndef NDEBUG
FunctionPass *createPPCCTRLoopsVerify();
#endif
FunctionPass *createPPCEarlyReturnPass();
FunctionPass *createPPCBranchSelectionPass();
FunctionPass *createPPCISelDag(PPCTargetMachine &TM);
FunctionPass *createPPCJITCodeEmitterPass(PPCTargetMachine &TM,
JITCodeEmitter &MCE);
void LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
[PowerPC] Always use "assembler dialect" 1 A setting in MCAsmInfo defines the "assembler dialect" to use. This is used by common code to choose between alternatives in a multi-alternative GNU inline asm statement like the following: __asm__ ("{sfe|subfe} %0,%1,%2" : "=r" (out) : "r" (in1), "r" (in2)); The meaning of these dialects is platform specific, and GCC defines those for PowerPC to use dialect 0 for old-style (POWER) mnemonics and 1 for new-style (PowerPC) mnemonics, like in the example above. To be compatible with inline asm used with GCC, LLVM ought to do the same. Specifically, this means we should always use assembler dialect 1 since old-style mnemonics really aren't supported on any current platform. However, the current LLVM back-end uses: AssemblerDialect = 1; // New-Style mnemonics. in PPCMCAsmInfoDarwin, and AssemblerDialect = 0; // Old-Style mnemonics. in PPCLinuxMCAsmInfo. The Linux setting really isn't correct, we should be using new-style mnemonics everywhere. This is changed by this commit. Unfortunately, the setting of this variable is overloaded in the back-end to decide whether or not we are on a Darwin target. This is done in PPCInstPrinter (the "SyntaxVariant" is initialized from the MCAsmInfo AssemblerDialect setting), and also in PPCMCExpr. Setting AssemblerDialect to 1 for both Darwin and Linux no longer allows us to make this distinction. Instead, this patch uses the MCSubtargetInfo passed to createPPCMCInstPrinter to distinguish Darwin targets, and ignores the SyntaxVariant parameter. As to PPCMCExpr, this patch adds an explicit isDarwin argument that needs to be passed in by the caller when creating a target MCExpr. (To do so this patch implicitly also reverts commit 184441.) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185858 91177308-0d34-0410-b5e6-96231b3b80d8
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AsmPrinter &AP, bool isDarwin);
/// \brief Creates an PPC-specific Target Transformation Info pass.
ImmutablePass *createPPCTargetTransformInfoPass(const PPCTargetMachine *TM);
namespace PPCII {
/// Target Operand Flag enum.
enum TOF {
//===------------------------------------------------------------------===//
// PPC Specific MachineOperand flags.
MO_NO_FLAG,
/// MO_DARWIN_STUB - On a symbol operand "FOO", this indicates that the
/// reference is actually to the "FOO$stub" symbol. This is used for calls
/// and jumps to external functions on Tiger and earlier.
MO_DARWIN_STUB = 1,
/// MO_PIC_FLAG - If this bit is set, the symbol reference is relative to
/// the function's picbase, e.g. lo16(symbol-picbase).
MO_PIC_FLAG = 2,
/// MO_NLP_FLAG - If this bit is set, the symbol reference is actually to
/// the non_lazy_ptr for the global, e.g. lo16(symbol$non_lazy_ptr-picbase).
MO_NLP_FLAG = 4,
/// MO_NLP_HIDDEN_FLAG - If this bit is set, the symbol reference is to a
/// symbol with hidden visibility. This causes a different kind of
/// non-lazy-pointer to be generated.
MO_NLP_HIDDEN_FLAG = 8,
/// The next are not flags but distinct values.
MO_ACCESS_MASK = 0xf0,
/// MO_LO, MO_HA - lo16(symbol) and ha16(symbol)
MO_LO = 1 << 4,
MO_HA = 2 << 4,
MO_TPREL_LO = 4 << 4,
MO_TPREL_HA = 3 << 4,
/// These values identify relocations on immediates folded
/// into memory operations.
MO_DTPREL_LO = 5 << 4,
MO_TLSLD_LO = 6 << 4,
MO_TOC_LO = 7 << 4,
// Symbol for VK_PPC_TLS fixup attached to an ADD instruction
MO_TLS = 8 << 4
};
} // end namespace PPCII
} // end namespace llvm;
#endif